Siberian Chiffchaff

The Siberian chiffchaff (Phylloscopus collybita tristis) is a dull bird, grey or brownish above and whitish below with little yellow, and its buff-white eyebrow is often longer than in western forms. It has a higher-pitched song and a short, high-pitched call, and it is usually treated as a subspecies of the common chiffchaff, though the two do not recognise each other's songs and it may be a full species (Wikipedia, general species account).

It breeds in Siberia east of the Pechora River and winters in the lower Himalaya, and is also regularly recorded in western Europe in winter. The source does not name Nepal and gives no habitat, diet or breeding detail (Wikipedia, general species account).